scholarly journals Bioinspired, graphene-enabled Ni composites with high strength and toughness

2019 ◽  
Vol 5 (5) ◽  
pp. eaav5577 ◽  
Author(s):  
Yunya Zhang ◽  
Frederick M. Heim ◽  
Jamison L. Bartlett ◽  
Ningning Song ◽  
Dieter Isheim ◽  
...  
Keyword(s):  
High Performance ◽  
2D Materials ◽  
High Hardness ◽  
High Strength ◽  
Limited Resources ◽  
Matrix Composites ◽  
Multiple Length Scales ◽  
Brick And Mortar ◽  
Hierarchical Architectures ◽  
Strength And Toughness

Nature’s wisdom resides in achieving a joint enhancement of strength and toughness by constructing intelligent, hierarchical architectures from extremely limited resources. A representative example is nacre, in which a brick-and-mortar structure enables a confluence of toughening mechanisms on multiple length scales. The result is an outstanding combination of strength and toughness which is hardly achieved by engineering materials. Here, a bioinspired Ni/Ni3C composite with nacre-like, brick-and-mortar structure was constructed from Ni powders and graphene sheets. This composite achieved a 73% increase in strength with only a 28% compromise on ductility, leading to a notable improvement in toughness. The graphene-derived Ni-Ti-Al/Ni3C composite retained high hardness up to 1000°C. The present study unveiled a method to smartly use 2D materials to fabricate high-performance metal matrix composites with brick-and-mortar structure through interfacial reactions and, furthermore, created an opportunity of developing advanced Ni-C–based alloys for high-temperature environments.

Neutron Diffraction Studies of Residual Stresses in Functionally Graded Alumina/Zirconia Ceramics

2008 ◽  
Vol 571-572 ◽  
pp. 309-314 ◽  
Author(s):  
Petr Lukáš ◽  
Miroslav Vrána ◽  
Jef Vleugels ◽  
Guy Anné ◽  
Omer Van der Biest
Keyword(s):  
Neutron Diffraction ◽  
Residual Stresses ◽  
High Performance ◽  
Construction Material ◽  
High Hardness ◽  
High Strength ◽  
Functionally Graded ◽  
Graded Materials ◽  
Lattice Strains ◽  
Constituent Phase

Graded Al2O3/Y-ZrO2 ceramics are developed to receive a construction material combining favourable properties of both constituent components, alumina (low wear rate, high hardness) and zirconia (high strength and toughness). The high performance of this material can be reached by optimising the internal residual stress distribution resulting mainly from phase specific stresses after cooling from the sintering temperature. For this purpose, non-destructive neutron diffraction mapping of residual stresses has been employed. However, the application of the conventional method does not provide straightforward results on macroscopic residual stresses. This experimental technique uses the crystal lattice plane as a built in microscopic strain gauge and the measured quantities are then lattice strains detected in each constituent phase separately. Based on these experimental resources, the paper proposes a procedure of separation of the residual macroscopic stress from phase specific stresses. The application of the presented method is demonstrated on functionally graded materials (FGM) prepared by electrophoretic deposition (EPD).

Preparation and Characterization of Reaction Sintering B4C/SiC Composite Ceramic

2014 ◽  
Vol 602-603 ◽  
pp. 536-539
Author(s):  
Hai Bin Sun ◽  
Yu Jun Zhang ◽  
Qi Song Li
Keyword(s):  
Fracture Toughness ◽  
High Performance ◽  
Bending Strength ◽  
Carbon Sources ◽  
High Hardness ◽  
High Strength ◽  
Composite Ceramic ◽  
High Fracture Toughness ◽  
Reaction Sintering ◽  
High Fracture

High hardness, high strength, high fracture toughness and low density are required for novel bulletproof materials. B4C/SiC composite ceramic is one of the most potential candidates. In this study, B4C/SiC composite ceramic was prepared by reaction sintering. The influence of B4C content, species and content of carbon, sintering temperature on the mechanical properties of B4C/SiC composite ceramic were studied. A high performance B4C/SiC composite ceramic was sintered at 1750°C for 30 min. Phenolic resin and carbon black were both chosen as carbon sources, whose favorable contents were 10wt%, 5wt%, respectively. The density of sintered bodies reduces with B4C content increases. To some extent, fracture toughness, bending strength improve initially and then deteriorate with the increase of B4C content whose optimal amount is 30wt%. The optimal fracture toughness and bending strength of the B4C/SiC composite ceramic are 5.07MPa·m1/2 and 487MPa, respectively. Meanwhile, the Viker-hardness of the sintered body is 30.2GPa, the density is as low as 2.82g/cm3.

Preparation and Characterization of Fe/SiC Ceramic-Metal Composites

2010 ◽  
Vol 434-435 ◽  
pp. 66-68 ◽  
Author(s):  
Zhong Sheng Liu ◽  
Gang Shao ◽  
De Liang Chen ◽  
Rui Zhang
Keyword(s):  
Bending Strength ◽  
Low Cost ◽  
High Hardness ◽  
High Strength ◽  
Precipitation Method ◽  
High Wear Resistance ◽  
Matrix Composites ◽  
Composite Powders ◽  
Pressing Method ◽  
Sic Composites

SiC is a perfect reinforced material, characteristic of high hardness, high wear- and corrosion-resistant property, and low cost. SiC-reinforced iron-matrix composites show high wear resistance, high hardness, high inflexibility and high strength, with wide applications as superior wear-resistant and high temperature materials. This paper reported a heterogeneous precipitation method to coat SiC with copper particles. The vacuum hot-pressing method was used to sinter the Fe/SiC composites with Cu-coated SiC powders. The techniques of XRD and SEM were used to characterize the compositions and microstructures of the samples. The Archimedes method was used to test the density. The results showed that SiC and Cu were homogeneously mixed in the composite powders obtained by the heterogeneous deposition method, and that the composites with 5wt% of SiC (Cu) obtained at 950°C have a high relative density of 96%, a high hardness of 4121 MPa and a high bending strength of 646 MPa. The enhanced properties of Fe/SiC composites could result from the improved interfacial consistency by using Cu-coated SiC powders, which could inhibit some adverse interfacial reactions.

scholarly journals Recent studies on particulate reinforced AZ91 magnesium composites fabricated by Stir casting – A review

2020 ◽  
Vol 4 (2) ◽  
pp. 115-126
Author(s):  
Anil K. Matta ◽  
Naga S. S. Koka ◽  
Sameer K. Devarakonda
Keyword(s):  
High Performance ◽  
Matrix Material ◽  
Weight Ratio ◽  
High Strength ◽  
Casting Process ◽  
Stir Casting ◽  
Critical Conditions ◽  
Matrix Composites ◽  
The Matrix ◽  
Magnesium Composites

Magnesium Metal Matrix Composites (Mg MMC) have been the focus of consideration by many researchers for the past few years. Many applications of Mg MMCs were evolved in less span of time in the automotive and aerospace sector to capture the benefit of high strength to weight ratio along with improved corrosion resistance. However, the performance of these materials in critical conditions is significantly influenced by several factors including the fabrication methods used for processing the composites. Most of the papers addressed all the manufacturing strategies of Mg MMC but no paper was recognized as a dedicated source for magnesium composites prepared through stir casting process. Since stir casting is the least expensive and most common process in the preparation of composites, this paper reviews particulate based Mg MMCs fabricated with stir casting technology. AZ91 series alloys are considered as the matrix material while the effect of different particle reinforcements, sizes , weight fractions on mechanical and tribological responses are elaborated in support with micro structural examinations. Technical difficulties and latest innovations happened during the last decade in making Mg MMCs as high performance material are also presented.

scholarly journals Fatigue and Fracture Behavior of Al6061-B4C Aluminium Matrix Composites

2020 ◽  
Vol 9 (4) ◽  
pp. 2121-2125
Keyword(s):  
Fracture Toughness ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Density Ratio ◽  
High Hardness ◽  
High Strength ◽  
Casting Process ◽  
Matrix Composites ◽  
Reaction Products ◽  
Automobile Engineering

In the present day engineering design and development activities many Scientists, Researchers and Engineers are striving hard to develop new and better engineering materials, which accomplishes high strength, low weight and energy efficient materials since the problems of environment and energy are major threshold areas. The development of new materials is growing day by day to replace the conventional materials in aerospace, marine engineering, automobile engineering industries etc., Hence, composite materials are found to be an alternative. A variety of metals and their alloys such as Aluminum, Magnesium and Titanium are comprehensively used as matrix materials. Among these Aluminium alloys have been used extensively, because of their excellent strength, low density, corrosion resistance and toughness. Similarly, many researchers have attempted to develop aluminum based metal matrix composites using different reinforcements such as SiC, Al2O3, B4C, TiC, TiO2, B4C etc., are added to the matrix to get required MMC’s. Among these reinforcements, B4C emerged as an exceptional reinforcement due to its high strength to density ratio, possesses high hardness and avoid the formation of interfacial reaction products with aluminum. Hence, in this paper attempts are made to fabricate Al 6061-3, 6, 9 and 12 wt.% B4C metal matrix composites by stir casting process to study fatigue life and fracture toughness as per ASTM standards. It is evident that fatigue strength and fracture toughness of the composites were enhanced with the addition of the wt.% of the reinforcement.

Experimental Investigation of Aluminium Hybrid Composites Reinforced with ZnS, TiO2 and BaTiO3 Produced Through Powder Metallurgy

2021 ◽  
Vol 13 (3) ◽  
Author(s):  
S. Rajeshkannan ◽  
I. Manikandan ◽  
M. Vigneshkumar
Keyword(s):  
Powder Metallurgy ◽  
Hybrid Composites ◽  
Brinell Hardness ◽  
High Hardness ◽  
High Strength ◽  
Hardness Test ◽  
Matrix Composites ◽  
X Ray Diffraction ◽  
Testing Instrument ◽  
X Ray

Semiconductors like ZnS, TiO2 and BaTiO3 were reinforced with Al-Al2O3 Metal Matrix Composites (MMCs) and were made through powder metallurgy in order to have high strength, high hardness and good thermal conductivity compared with conventional materials. Three MMC of test specimens were prepared with varying reinforcement ratio Al-Al2O3-ZnS(94-5-1), Al-Al2O3-TiO2(94-5-1), Al-Al2O3-BaTiO3(94-5-1) percentage by weight respectively. The hardness test has been made by using Brinell hardness testing instrument. Hardness test revealed that the addition of reinforcement TiO2, BaTiO3 increases the hardness value. However, the addition of ZnS to the Al-Al2O3 MMCs showed decrease in the hardness value. The crystal structure of the 3 composites were examined through X-Ray Diffraction (XRD) peaks.

Electrical Discharge Machining of Alumina-Zirconia-TiC Composites with Varying Zirconia Content

2013 ◽  
Vol 554-557 ◽  
pp. 1916-1921 ◽  
Author(s):  
Richard Landfried ◽  
Frank Kern ◽  
Rainer Gadow
Keyword(s):  
Electrical Discharge ◽  
Bending Strength ◽  
High Hardness ◽  
High Strength ◽  
Ceramic Composites ◽  
Matrix Composition ◽  
Pure Alumina ◽  
Electrically Conductive ◽  
Pure Zirconia ◽  
Strength And Toughness

Ceramic injection molding (CIM) or extrusion requires molds and dies with high hardness to reduce tool wear which occurs due to processing of highly abrasive ceramic compounds. Besides the wear resistance high strength and toughness are necessary for mold materials to withstand the loads during application. Recent work of the authors has shown the high potential of electrical discharge machinable ceramic composites based on oxide ceramic matrices for high wear applications. The use of alumina zirconia composites (AZC) as matrix for electrically conductive composites enables the combination of high hardness of alumina and high strength and toughness of zirconia in order to customize the properties of the mold material. This study focuses on development of ED machinable AZCs with addition of 24 vol.-% titanium carbide as electrically conductive phase. The composition of the matrix was varied from pure alumina to pure zirconia in 5 steps. Disks for mechanical and electrical characterization and electric discharge machining experiments were manufactured by hot pressing. Results show that hardness, strength and toughness can be almost linearly correlated to composition from pure alumina matrix with a 4-point bending strength of 430 MPa, a hardness of 2250 HV10 and a toughness of 3.7 MPa√m to pure zirconia matrix with 1020 MPa bending strength, 1490 HV10 and a toughness of 5.9 MPa√m. Variation of matrix composition also leads to significantly different EDM characteristics. The material removal rate shows a maximum at 19 vol.-% zirconia and 58 vol.-% alumina while surface roughness of the machined composites decreases significantly with increasing zirconia amount. SEM and EDX analysis were made to identify removal mechanisms of each ceramic matrix phase. It was found that alumina tends to be removed by vaporization due to electrical discharges. Zirconia, which has a higher melting and vaporization point than alumina melts during the formation of the plasma channel. Zirconia cannot be removed in total from the surface but forms a smooth and compact amorphous layer of resolidified material on both sample and electrode.

Nanocrystalline Diamond Coated Tool Performance in Machining of LM6 Aluminium Alloy/Alumina MMC

2015 ◽  
Author(s):  
Ramasubramanian Kannan ◽  
Arunachalam Narayanaperumal ◽  
Mamidanna Sri Ramachandra Rao
Keyword(s):  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Weight Ratio ◽  
High Hardness ◽  
High Strength ◽  
Matrix Composites ◽  
Aerospace Applications ◽  
Coated Tools ◽  
Nano Crystalline ◽  
Improved Performance

Aluminium based metal matrix composites (MMC) gain its importance in automotive and aerospace applications due to their high strength to low weight ratio, which leads to reduced fuel consumption and improved performance. However the usage of MMC is limited due to its poor machinability. The presence of hard reinforcing particles in MMC makes these materials difficult to machine. A cutting tool with high hardness and low coefficient of friction is required for machining this MMC material effectively. In this paper a comparative study on machinability of different coated tools on LM6 aluminum alloy/alumina MMC are conducted and presented. Experimental results on tool wear, cutting force and surface finish indicate that nano-crystalline diamond coated tools (NCD) outperform the other commercially available coated tools for machining this metal matrix composites.

High Strength Natural Fibers for Improved Polymer Matrix Composites

2010 ◽  
Vol 638-642 ◽  
pp. 961-966 ◽  
Author(s):  
Sérgio Neves Monteiro ◽  
Kestur Gundappa Satyanarayana ◽  
Felipe Perissé Duarte Lopes
Keyword(s):  
Polymer Composites ◽  
High Performance ◽  
Polymer Matrix Composites ◽  
Natural Fibers ◽  
High Strength ◽  
Strengthening Mechanism ◽  
Matrix Composites ◽  
Lignocellulosic Fibers ◽  
High Performance Fiber ◽  
Curaua Fibers

A statistical evaluation based on the Weibull method was performed to correlate the mechanical properties and the diameter of different lignocellulosic fibers. The sisal, rami and curaua fibers were found to have a hyperbolic correlation between their ultimate strength and diameter. This permitted to select thinner high strength fibers, with over 1000 MPa, as reinforcement for the strongest polymer composites ever fabricated with these fibers. A structural analysis was conducted by electron microscopy to identify the strengthening mechanism for both, the high performance fiber and their improved polymer composites.

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